Abstract: In order to address the engineering challenges of controlling the stability of the regenerated roof in the layer filling mining of steeply dipping coal seam, uniaxial compression tests are conducted on processed slurry-coal composite specimens with different height ratios. The mechanical properties and deformation evolution laws of the slurry-coal composite are investigated, and the failure morphology and mechanical damage characteristics of the specimens are analyzed using techniques such as digital imaging and acoustic emission detection. The research results indicate that the overall compressive strength of the composite specimens is negatively correlated with the proportion of coal content. Two main types of failure modes are observed in specimens with different height ratios of slurry-coal composite. Type I （3∶7, 7∶3） where the failure propagation direction mainly follows the loading direction of the slurry-coal composite, and Type II （6∶4, 5∶5, 4∶6） where the failure extends along the interface direction and loading direction of the composite specimens. The failure mechanism is manifested as Type I failure, where the coal body first reaches the interface compressive strength and undergoes tensile failure, and then the load on the slurry also reaches its own strength, forming a through type tensile failure consistent with the loading direction. Type II failure, where the load on the coal body first exceeds its tensile strength, resulting in the formation of tensile cracks. With continued loading, the interface strength and slurry tensile strength are exceeded, leading to the formation of penetrating cracks composed of interface cracks and tensile cracks. The research results provide a theoretical basis for the prevention and control of failure and instability in slurry-coal composite in the filling mining of steeply dipping coal seams.